Related Party Transactions - Additional Information (Detail) (USD $)	3 Months Ended
	Feb. 28, 2013	Feb. 29, 2012	Nov. 30, 2012
Related Party Transaction [Line Items]
Purchase commitments	$ 171,400,000
Loans outstanding to certain employees	41,300,000		46,500,000
Commissions for conducting brokerage services	131,083,000	117,499,000
Private Equity Related Funds [Member]
Related Party Transaction [Line Items]
Equity investments loans in related funds	102,700,000		104,200,000
Interest income earned on loans	500,000	800,000
Other revenues (gain) and investment income (loss)	900,000	(4,800,000)
Leucadia [Member]
Related Party Transaction [Line Items]
Commissions for conducting brokerage services	5,000.0	8,300,000
Earnings associated with their investment	$ 61,000	$ 0